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Friday, 30 September 2011

We keep finding out that all kinds of people are reading our blog, when you email us, or when we say 'hey, you should totally read our blog' and you say 'I already do!'. Lots of you don't comment much, though, so we never find out who you are and we're actually quite interested.

So if you read us, take a moment to leave us a comment below. Introduce yourselves, tell us a little bit about what you do and why you're reading us, and, if you blog and whatnot yourself, feel free to leave links for people to find your stuff too.

Also, please feel free to comment on things if you want to; we both see comments on any posts, even the old ones, and we like the attention! Plus we've had some great conversations with some of you who do comment, and begun all kinds of collaborations and things, and one thing we want from the blog is to open some lines of communication on our flavour of psychology that doesn't get a lot of traction in other, more mainstream blogs.

Friday, 23 September 2011

One of the bugbears of direct perception is the fact of neural delays. The transmission of signals through the nervous system takes time, and this means that there is a lag between something happening (at, say, the retina) and that event having consequences in cortex, let alone behaviour. In control theory terms, delays in a system can lead to instability in that system's behaviour as you are forced to make corrections that are then incorrect and must themselves be corrected.

It's typically suggested in psychology that these delays are compensated for via computational predictions; the nervous system 'perceives the present' by taking the lagged input and using it as the basis of a guess about what's going on now (e.g. Changizi et al, 2008, plus see this post from a while back). This is a problematic idea: if the perceptual control of actions is based on a guess compensating for a variable time lag, then the stability issue remains, not to mention the consequences for mis-predicting the future. Regardless, it's not really an option for a theory of direct perception, and I want to discuss a couple of options.

The third prediction was that the detection of relative direction was conditioned on the relative speed; the latter was simply a noise term. de Rugy, Oullier & Temprado (2008) tested this prediction by using an amplitude manipulation to alter the relative speeds. Their data did not support the model predictions, and they concluded that the approach taken by the Bingham model was flawed. We recently replicated their experiment (Snapp-Childs, Wilson & Bingham, in press as of Friday; download) and identified numerous critical flaws in their design and analysis which invalidated their criticism.

Tuesday, 6 September 2011

I'm writing a grant proposal, and part of the process involves a 4000 character lay summary of the project; what I'm up to, what the objectives are and who the likely beneficiaries are. The goal is for this to be in language a non-expert can understand (Research Councils use these summaries when they promote funded grants to the wider public). I am, frankly, cursed with too much knowledge, and pitching these lay summaries is always a challenge. What I would like is for people, especially non-experts, to have a look at the text below and give me feedback - are there sections that aren't popping? Sentences that aren't clear? Entire sections that seem a bit mysterious?

Please feel free to leave comments pointing out things that aren't working (and things that are, too, actually: it's good for me to get a feeling for what I'm doing right here). If you felt like spreading this around via Twitter, G+, whatever your fancy, I'd appreciate all and any feedback on this!